Yep. Yesterday I had just got back from a 400 mile round trip to see my old man in hosp, but it's fairly normal to be up late....
I sometimes try to fight it, but my body-clock definitely prefers the day to start in the afternoon and end in the morning! I'm much more productive later too. Think it's fairly common in this game really, but hard to explain to peeps with normal jobs. What about you, mate?